Paint brush



Oct. 4, 1966 R38. HARRISON 3,276,063

PAINT BRUS H Filed Nov. 15 1965 FIGS INVENTOR. RICHARD S. HARRISONATTORNEYS United States Patent 3,276,063 PAINT BRUSH Richard S.Harrison, Lancaster, New Brunswick, Canada, assignor to T. S. Simms &Co. Limited, New Brunswick, Canada Filed Nov. 15, 1965, Ser. No. 507,7534 Claims. (Cl. -171) This invention relates to the manufacture of paintbrushes and is particularly concerned with a method of attaching brushferrules to plastic handles.

A recent trend in the manufacture of paint brushes has been to employplastic rather than wooden handles. This trend has recently receivedimpetus through the promotion of polypropylene as handle material. Theprice of this particular plastic has made the plastic handle competitivein price with the wooden handle. However, due to the incompressibilityof polypropylene and other plastics, certain manufacturing difficultieshave been encountered in attaching brush ferrules to the handles. As iswell known to those in the trade, the term ferrule is applied to themild steel band which is used to hold the bristle knot at one end andthe handle at the other. The two common methods of holding the handlewithin the ferrule has been to drive short nails through the flat facesof the ferrule and into the handle or to use a crimper as to displaceportions of the fiat faces of the ferrule into the body of the handle.It has been found that while the nailing of ferrules to plastic handleshas given a good tensile and bonding strength, the nails cannot be madeto remain completely submerged in the plastic. The plastic displaced bythe nail causes a ridge of plastic to build up under the ferrule wherebyto lift the ferrule away from the handle and expose the sharp edges ofthe ferrule. This effect not only endangers the user, but is detrimentalto the appearance of the brush as well.

Crimping also causes plastic displacement and in this case, the liftingof the ferrule by the upwelled plastic reduces the holding strength ofthe crimps. For this reason, the crimping of ferrules into plastichandles has been limited to smaller brushes up to two inches in width.With larger brushes the greater width of the ferrules across the flatsof the brush has caused the centremost crimps to lift entirely free fromthe depressions in the plastic. Even with the smaller brushes, theholding strength of the crimps has been marginal.

As suggested above, the manufacturing difficulties encountered in usingplastic handles have been largely due to the incompressibility ofplastic. Where nails are used, the resultant upward bulging of theplastic, while not always interfering with the holding strength of thenails, raises the edges of the ferrule to present a hazard to the userand to make the brush unattractive in appearance. In the case ofcrimping, the bulging of the plastic reduces the holding strength of thecrimps so that brushes wider than two inches cannot be crimped at alland crimping of the smaller brushes has not been entirely satisfactory.

It is, therefore, an object of this invention to provide an improvedmethod of manufacturing paint brushes with plastic handles.

It is a more specific object of the invention to provide a method ofcrimping ferrules to plastic brush handles which avoids the difficulties.previously encountered in crimping operations due to theincompressibility of the plastic.

It is a further and related object of the invention to provide a methodof crimping ferrules to brush handles which is adapted to themanufacture of brushes of any size.

Patented Oct. 4, 1966 "ice It is a still further object of the inventionto provide a paint brush in which the ferrule is attached to the plastichandle by crimps of particular type and location.

The above and further objects of the invention are gained by crimpingferrules to plastic handles along the side edges of the brushes. In apreferred embodiment of the invention the crimping is carried out at thecorners of the ferrule.

The above and further objects of the invention and the method in whichthese objects are achieved will be more thoroughly understood from thefollowing description of preferred embodiments of the invention as readin conjunction with the accompanying drawings.

In the drawings,

FIG. 1 is a perspective view of a paint brush having a plastic handleand manufactured in accord with a first preferred embodiment of theinvention;

FIG. 2 is an enlarged view of a portion of FIG. 1 to illustrate ingreater detail the location and nature of the crimps holding the ferruleto the handle;

FIG. 3 is an enlarged vertical cross-sectional view taken along the line33 of FIG. 1 and further showing a crimping die in the action of forminga crimp in the ferrule;

FIG. 4 is an enlarged view of a portion of FIG. 3; and

FIG. 5 is a view similar to the right-hand end of FIG. 3 but showing analternative form and position of crimp.

Referring to FIG. 1, the paint brush illustrated essentially consists ofa knot of bristles or other filling material 10, a mild steel ferrule12, and a handle 14. In this regard, it will be appreciated that thesethree items are the normal components in any paint brush and that thepresent invention relates to the particular manner illustrated forattaching the ferrule to the handle.

Prior to the present invention, the common methods of fixing the ferruleto the handle have been to drive nails or form crimps in the flat faces12a and 12b of the ferrule. Either of these methods has served well infixing ferrules to wooden handles but with the recent introduction ofplastic handles, both methods have disadvantages. More particularly, thecrimping operation which is now preferred by most brush manufacturershas proved to be quite inadequate in fixing ferrules to plastic handles,particularly with the larger brushes.

The difiiculties met heretofore have been due to two factors, namely,the practice of forming the crimps in the flat faces of the ferrule andthe incompressibility of plastic. It has been found that when the crimpsare formed in the ferrule as to drive small areas of the ferrulematerial downwardly into the brush handle, the incompressibility of theplastic has caused the latter to flow upwardly around the downwardlydisplaced ferrule material. This upward welling of the plastic has, inturn, tended to lift the ferrule away from the handle body, thereforereducing the actual bite effected by the crimps. This effect has beenfound to be most serious in brushes over two inches in width as thegreater flexibility of the wider ferrule has resulted in a completelifting away of the ferrule, particularly at the centre thereof. Even inthe case of the smaller brushes, the strength with which the handle isgripped by the crimped ferrule has been so poor that it has beenpossible to very easily tear the ferrule off the handle when painting inthe normal manner.

In accord with the present invention, the above noted difficulties areovercome by forming crimps along the side edges of the brush. By sodoing, not only are the detrimental effects due to the incompressiblityof the plastic avoided but this same feature is actually used to goodadvantage. The upward welling of the plastic is used as a means ofstretching the fiat faces of the 3 ferrule as to pull them down tightlyagainst the handle body. This stretching of the flat faces of theferrule in turn tends to hold the crimps formed in the ferrule materialwithin the detents formed in the plastic as the crimps are developed.Apart from the surprisingly much greater holding strength in the crimps,the appearance of the brush is improved because there are no crimps onthe flat main faces of the ferrule and these flat areas lie tightlyagainst the handle body. This has the further beneficial effect ofavoiding the exposure of ferrule edges which might endanger the brushuser.

In accord with the preferred embodiment of the invention as shown inFIGS. 1 to 4, the crimps the crimps 16 are formed at the corners of theferrule. This is a preferred expedient for two reasons. Firstly, almostall ferrules are formed with an overlap at one side edge of the brush sothat crimps formed along the centre line of the side edge would have topenetrate two thicknesses of material. Secondly, centre line crimpsoffer points around which the ferrule might pivot during the normalpainting action. However, it should be clearly understood that thepresent invention contemplates crimps effected anywhere in the sideedges of the ferrule as in all cases the desired stretching of the flatfaces of the ferrule is achieved.

In forming the crimps at the preferred corner locations, the crimpingoperation is carried out with vertical travelling dies as shown in FIG.3. Where the corners are round, which is the normal configuration, thedies contact the corners at the points where the radiants which extendat 45 to the plane of the handle contact the corners. This is shown inFIG. 4. As also shown in FIG. 4, the resultant Welling up of the plastictakes place largely at point 18, i.e. below the crimp, and tends to pushthe side edge of the ferrule slightly outward which contributes to thestretching of the flat faces 12a and 12b of the ferrule. Ideally, thevertical travelling die is driven to a depth in the plastic which willcause the majority of the rebounding plastic to push outwardly alongthose radiants which extend approximately at 30 to the plane of thehandle which lie closest to the midplane of the handle so that thehorizontal component of the force exerted by this upwelling plastic willbe suf- Iicient to stretch the flat faces of the ferrule but not sogreat as to push the side edges of the ferrule out of the recessesformed in the plastic by the crimps. The crimp 16a shown in FIG. '5 ismade on the approximate centre line of the side edge of the ferrule andadequately serves to stretch the flat faces of the ferrule to gain theadvantages of the present invention. As mentioned above, however, thiscentre line crimp will on one side of the brush have to be passedthrough two thickenesses of ferrule material and it also tends to set uppoints about which the ferrule might pivot when the brush is used in thenormal fashion. :Further, the centre line crimp must be formed withhorizontal travelling dies and as most brush manufacturing machines movebrushes along the flat faces of the ferrule with the length of the brushat right angles to the direction of motion, the horizontal travellingdies would be more cumbersome than vertical travelling dies. It will beappreciated that it is within the scope of this invention that side edgecrimps may be formed positioned at other than the corners or centre lineof the side edges as in all cases the desired stretching of the flatfaces of the ferrule would be achieved. The invention resides in theconcept of effecting the crimps anywhere in the side edges although thepreferred embodiment consists of effecting the crimps at the corners.

What I claim as my invention is:

1. A paint brush comprising a plastic handle having an elongated handlegrip portion and terminating inan integral ferrule receiving bodyportion, said body portion having opposed elongated flat faced parallelside Wall surfaces and shorter curved end wall surfaces, therebyaffording four curved corners substantially located at the points wherethe flat side wall surfaces meet the curved end wall surfaces, a tubularmetal ferrule tightly engaged about the surfaces of said side walls andsaid end walls, and means for holding said ferrule on said handle, saidholding means consisting of four crimps, one at each of said curvedcorners, each of said crimps being of a depth in said body portionsuflicient to cause outward Welling of plastic material adjacent to eachof said crimps whereby said outward Welling tends to push the end wallportions of the ferrule slightly outward thereby resulting in astretching of the ferrule along the flat faces of said side wallsurfaces.

2. A paint brush comprising a plastic handle having an elongated handlegrip portion and terminating in an integral ferrule receiving bodyportion, said body portion having opposed elongated flat faced parallelside wall surfaces and shorter rounded end wall surfaces, therebyaffording four curved corners substantially located at the points wherethe flat side wall surfaces meet the rounded end wall surfaces, atubular metal ferrule tightly engaged about the surfaces of said sidewalls and said end walls, and means for holding said ferrule on saidhandle, said holding means consisting of four crimps, one at each ofsaid curved corners, each of said crimps being of a depth in said bodyportion sufiicient to cause outward Welling of plastic material adjacentto each of said crimps whereby said outward Welling tends to push theend wall portions of the ferrule slightly outward thereby resulting in astretching of the ferrule along the fiat faces of said side wallsurfaces, said crimps being formed in said curved corners at pointslocated by radiants commencing at the centre about which said roundedend walls are generated and extending at 45 to said fiat parallel sidewall surfaces.

3. A method of attaching a tubular metal ferrule to a plastic paintbrush handle having an elongated handle grip portion and terminating inan integral ferrule receiving body portion, said body portion havingopposed elongated flat faced parallel side wall surfaces and shortercurved end wall surfaces, thereby affording four curved cornerssubstantially located at the points where the flat side wall surfacesmeet the curved end wall surfaces, said method comprising the steps ofsliding said ferrule onto said ferrule receiving body portion and fixingsaid ferrule to said body portion by crimping said ferrule at each ofsaid four curved corners to a suifioient depth to cause outward Wellingof plastic material adjacent to each of said crimps whereby said outwardWelling tends to push the end wall portions of the ferrule slightlyoutward thereby resulting in .a stretching of the ferrule along the flatfaces of said side wall surfaces.

4. A method of attaching a tubular metal ferrule to a plastic paintbrush handle having an elongated handle grip portion and terminating inan integral ferrule receiving body portion, said body portion havingopposed I elongated flat faced parallel side wall surfaces and shorterrounded end wall surfaces, thereby affording four curved cornerssubstantially located at the points where the flat side wall surfacesmeet the rounded end wall surfaces, said method comprising the steps ofsliding said ferrule onto said ferrule receiving body portion and fixingsaid ferrule to said body portion by crimping said ferrule at each ofsaid four curved corners to a suflicient depth to cause outward Wellingof plastic material adjacent to each of said crimps whereby said outwardWelling tends to'push the end wall portions of the ferrule slightlyoutward thereby resulting in a stretching of the ferrule along the flatfaces of said side wall surfaces, said crimps being formed in saidcurved corners at points located by radiants commencing at the centreabout which said rounded end walls are generated and extending at 45 tothe said fiat parallel side wall surfaces.

(References on following page) 6 References Cited by the ExaminerFOREIGN PATENTS U I STATES PATENTS 1,311,937 11/1962 France.

582,657 11/19'4 6 Great Britain. 1,436,916 11/1922 Shulman et a1. 300-211,767,349 /1930 Cross 15--143 5 CHARLES A. WI LLMU'IH, Primary Examiner,2,854,684 10/1958 Hardman et a1. 15193 PETER FELDIMAN, AssistantExaminer.

1. A PAINT BRUSH COMPRISING A PLASTIC HANDLE HAVING AN ELONGATED HANDLEGRIP PORTION AND TERMINATING IN AN INTEGRAL FERRULE RECEIVING BODYPORTION, SAID BODY PORTION HAVING OPPOSED ELONGATED FLAT FACED PARALLELSIDE WALL SURFACES AND SHORTER CURVED END WALL SURFACES, THEREBYAFFORDING FOUR CURVED CORNERS SUBSTANTIALLY LOCATED THEREBY THE POINTSWHERE THE FLAT SIDE WALL SURFACES MEET THE CURVED END WALL SURFACES, ATUBULAR METAL FERRULE TIGHTLY ENGAGED ABOUT THE SURFACES OF SAID SIDEWALLS AND SAID END WALLS, AND MEANS FOR HOLDING SAID FERRULE ON SAIDHANDLE, SAID HOLDING MEANS CONSISTING OF FOUR CRIMPS, ONE AT EACH OFSAID CURVED CORNERS, EACH OF SAID CRIMPS BEING OF A DEPTH IN SAID BODYPORTION SUFFICIENT TO CAUSE OUTWARD WELLING OF PLASTIC MATERIAL ADJACENTTO EACH OF SAID CRIMPS WHEREBY SAID OUTWARD WELLING TENDS TO PUSH THEEND WALL PORTIONS OF THE FERRULE SLIGHTLY OUTWARD THEREBY RESULTING IN ASTRETCHING OF THE FERRULE OUTWARD FLAT FACES OF SAID SIDE WALL SURFACES.